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It’s still interesting to study Ptolemy because of the role he played in the history of science and the scientific method. Rigorous scientific practice isn’t so

It’s still interesting to study Ptolemy because of the role he played in the history of science and the scientific method. Rigorous scientific practice isn’t something we walked out of the jungle having mastered, it took centuries to develop after many missteps such as Ptolemy’s. Furthermore, one of the lessons we learned from the bad assumptions of Ptolemy (geocentrism) is to never assume that we occupy a special position from which we make observations. This holds value even in modern cosmology, since it appears that we’re at the “centre” of the universe due to the cosmic microwave background’s extreme uniformity in every direction. Cosmologists thus assume that we’re not special, so we are unlikely to be at the centre of anything, which leads to the term “observable universe” and the potential for the universe to be much larger than this region from which all light has reached us.

rurban 4y ago
The criticism by several well known astronomists: Tycho Brahe called out betrayal 1600. Jean-Baptiste Joseph Delambre 1817 called it fake and fabricated observations, preconceptions, lies and plagiarism. The US astronom Robert Russell Newton confirmed it 1985. B. L. van der Waerden confirmed it 1988. It was about the non-scientific methods, not the absurd results, given that the heliocentric view was known long before Ptolemy.
- chongli 4y ago
  This is getting too far into the weeds on judging Ptolemy's intentions and motivations. It also applies more modern standards of scientific rigour to work that was done before they existed. This is a common anachronism (and fallacy) people make throughout history. the heliocentric view was known long before Ptolemy I am aware that Aristarchus of Samos put forth a heliocentric view. Unfortunately for him, it wouldn't be until the development of Kepler's Laws (ca. 1609-1619) that a heliocentric model could be made to yield better predictions (in all cases) than the Ptolemaic model. Yes, even though Copernicus developed the more modern heliocentric theory (before 1543) he could not reduce the errors in his predictions because he held onto the assumption of perfect circular orbits dating back to Plato. Few astronomers at the time accepted his theory, and even Tycho Brahe (who you cite) constructed his own model which was mathematically equivalent to Copernicus's but placed the Earth at the centre of the system.
bazoom42 4y ago
> Furthermore, one of the lessons we learned from the bad assumptions of Ptolemy (geocentrism) is to never assume that we occupy a special position from which we make observations. The geocentric model does not assume “we” are in a special position. The center of the universe would be the center of the earth, not the point of the observer or any human. (But interestingly, in Dantes Comedy, the devil is placed in the center of the earth and hence the center of the universe.)
- chongli 4y ago
  In modern astronomy parlance, "we" refers to humans, i.e. earthlings, hence the earth. Placing the earth at the centre of anything in your theory is applying a human-centric bias to your ideas. Astronomers and cosmologists try to avoid that nowadays. When talking about deep space objects (such as distant galaxies), the centre of the earth vs. the surface is far below the noise floor in terms of distance.
  - lo_zamoyski 4y ago
    His point was that being at the spatial center does not automatically imply the sort of bias you and others seem to impute. Indeed, it would have been considered idolatrous and prideful to put Man at the center (who should prefer to reign in Hell rather than serve in Heaven?). God is at the center, in the ancient world but especially during the Medieval period. Someone once remarked that the spatial centrality of the earth was commonly understood as a kind of centrality within the lowest order of reality (Man himself is, in Catholic tradition, the lowest of the intellectual beings). This actually sheds some light on why the Incarnation is such a big deal. Compare this with the Jewish and Muslim rejection of the notion that God would lower Himself by entering and uniting with Creation in such an intimate way. If anything, it is the Enlightenment that dethrones God and installs Man at the center of concern. Modernism is in this sense a kind of worship of Man, and what is worship if not putting something at the center? I think people attach too much significance to the historical belief in geocentrism. It is a very reasonable default position to take given what is observable. Much of the mythology surrounding heliocentrism and how supposedly theologically disastrous it was is fabrication and Enlightenment propaganda.

rurban 4y ago

The criticism by several well known astronomists: Tycho Brahe called out betrayal 1600. Jean-Baptiste Joseph Delambre 1817 called it fake and fabricated observations, preconceptions, lies and plagiarism. The US astronom Robert Russell Newton confirmed it 1985. B. L. van der Waerden confirmed it 1988. It was about the non-scientific methods, not the absurd results, given that the heliocentric view was known long before Ptolemy.

chongli 4y ago
This is getting too far into the weeds on judging Ptolemy's intentions and motivations. It also applies more modern standards of scientific rigour to work that was done before they existed. This is a common anachronism (and fallacy) people make throughout history. the heliocentric view was known long before Ptolemy I am aware that Aristarchus of Samos put forth a heliocentric view. Unfortunately for him, it wouldn't be until the development of Kepler's Laws (ca. 1609-1619) that a heliocentric model could be made to yield better predictions (in all cases) than the Ptolemaic model. Yes, even though Copernicus developed the more modern heliocentric theory (before 1543) he could not reduce the errors in his predictions because he held onto the assumption of perfect circular orbits dating back to Plato. Few astronomers at the time accepted his theory, and even Tycho Brahe (who you cite) constructed his own model which was mathematically equivalent to Copernicus's but placed the Earth at the centre of the system.

bazoom42 4y ago

> Furthermore, one of the lessons we learned from the bad assumptions of Ptolemy (geocentrism) is to never assume that we occupy a special position from which we make observations. The geocentric model does not assume “we” are in a special position. The center of the universe would be the center of the earth, not the point of the observer or any human. (But interestingly, in Dantes Comedy, the devil is placed in the center of the earth and hence the center of the universe.)

chongli 4y ago
In modern astronomy parlance, "we" refers to humans, i.e. earthlings, hence the earth. Placing the earth at the centre of anything in your theory is applying a human-centric bias to your ideas. Astronomers and cosmologists try to avoid that nowadays. When talking about deep space objects (such as distant galaxies), the centre of the earth vs. the surface is far below the noise floor in terms of distance.
- lo_zamoyski 4y ago
  His point was that being at the spatial center does not automatically imply the sort of bias you and others seem to impute. Indeed, it would have been considered idolatrous and prideful to put Man at the center (who should prefer to reign in Hell rather than serve in Heaven?). God is at the center, in the ancient world but especially during the Medieval period. Someone once remarked that the spatial centrality of the earth was commonly understood as a kind of centrality within the lowest order of reality (Man himself is, in Catholic tradition, the lowest of the intellectual beings). This actually sheds some light on why the Incarnation is such a big deal. Compare this with the Jewish and Muslim rejection of the notion that God would lower Himself by entering and uniting with Creation in such an intimate way. If anything, it is the Enlightenment that dethrones God and installs Man at the center of concern. Modernism is in this sense a kind of worship of Man, and what is worship if not putting something at the center? I think people attach too much significance to the historical belief in geocentrism. It is a very reasonable default position to take given what is observable. Much of the mythology surrounding heliocentrism and how supposedly theologically disastrous it was is fabrication and Enlightenment propaganda.